MBTOWC(3) Linux Programmer's Manual MBTOWC(3)
mbtowc - convert a multibyte sequence to a wide character
int mbtowc(wchar_t *pwc, const char *s, size_t n);
The main case for this function is when s is not NULL and pwc is not
NULL. In this case, the mbtowc() function inspects at most n bytes of
the multibyte string starting at s, extracts the next complete multi-
byte character, converts it to a wide character and stores it at *pwc.
It updates an internal shift state only known to the mbtowc function.
If s does not point to a '\0' byte, it returns the number of bytes that
were consumed from s, otherwise it returns 0.
If the n bytes starting at s do not contain a complete multibyte char-
acter, or if they contain an invalid multibyte sequence, mbtowc()
returns -1. This can happen even if n >= MB_CUR_MAX, if the multibyte
string contains redundant shift sequences.
A different case is when s is not NULL but pwc is NULL. In this case
the mbtowc() function behaves as above, except that it does not store
the converted wide character in memory.
A third case is when s is NULL. In this case, pwc and n are ignored.
The mbtowc() function resets the shift state, only known to this func-
tion, to the initial state, and returns non-zero if the encoding has
nontrivial shift state, or zero if the encoding is stateless.
If s is not NULL, the mbtowc() function returns the number of consumed
bytes starting at s, or 0 if s points to a null byte, or -1 upon fail-
If s is NULL, the mbtowc() function returns non-zero if the encoding
has nontrivial shift state, or zero if the encoding is stateless.
The behavior of mbtowc() depends on the LC_CTYPE category of the cur-
This function is not multi-thread safe. The function mbrtowc(3) pro-
vides a better interface to the same functionality.
MB_CUR_MAX(3), mbrtowc(3), mbstowcs(3)
This page is part of release 3.05 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2001-07-04 MBTOWC(3)